Can't tell you how teens do it, a little bit older. The advice I would give is if there was something which made you deserve the pain, it would cause it.
The reason you believe you deserve to be in pain, has left you in emotional pain. As you can see it already hurts you, emotionally rather than physically. When designing the outcome, some things cause physical pain and some cause emotional pain, trust in He who made everything the outcome of doing something causes one, the other, or both, and recognize He doesn't want to hurt you further, sent for forgiveness, so the inherent pain is enough, and adding physical pain to emotional pain is to judge yourself more harshly than He would having created things with a limited pain potential, and is therefore needless inflict more.
friendinpeace